Remove redundant, unused decorators from RTE

These have since been replaced by decorators that operator whether in MD mode or otherwise. This might not be optimal because LINK entities do not appear in MD mode at all at the moment, but instead you see the ()[] md notation version.

src/RichText.js

@@ -113,31 +113,6 @@ let emojiDecorator = {
  * Returns a composite decorator which has access to provided scope.
  */
 export function getScopedRTDecorators(scope: any): CompositeDecorator {
-    let MemberAvatar = sdk.getComponent('avatars.MemberAvatar');
-
-    let usernameDecorator = {
-        strategy: (contentBlock, callback) => {
-            findWithRegex(USERNAME_REGEX, contentBlock, callback);
-        },
-        component: (props) => {
-            let member = scope.room.getMember(props.children[0].props.text);
-            // unused until we make these decorators immutable (autocomplete needed)
-            let name = member ? member.name : null;
-            let avatar = member ? <MemberAvatar member={member} width={16} height={16}/> : null;
-            return <span className="mx_UserPill">{avatar}{props.children}</span>;
-        }
-    };
-
-    let roomDecorator = {
-        strategy: (contentBlock, callback) => {
-            findWithRegex(ROOM_REGEX, contentBlock, callback);
-        },
-        component: (props) => {
-            return <span className="mx_RoomPill">{props.children}</span>;
-        }
-    };
-
-    // TODO Re-enable usernameDecorator and roomDecorator
     return [emojiDecorator];
 }